Processing techniques that are similar or equivalent to semiconductor processing techniques are often used to produce sensors on substrates. The substrate has a top surface and a bottom surface with sensing elements, wire bond pads and ancillary circuits usually formed or fixed on the top surface. The ancillary circuits often include resistors, amplifiers, and transistors. The substrates themselves can be quartz, glass, silicon, or other materials.
Those practiced in the art of semiconductor processing know of many techniques and processes for producing circuitry and sensors on substrates. They also know of techniques and process for digging deep trenches or holes in a substrate. In some cases the trenches or holes go entirely through the substrate. Holes passing completely through a substrate have been used for making electrical connections between the top and the bottom of the substrate. One reason for electrically connecting the top and the bottom substrate surfaces is that wire bond pads can be placed on the bottom of the substrate.
Many sensors suffer from the problem of having the ancillary circuitry, and bond pads exposed to the same environment as the sensing element. This can be a considerable problem when the environment is caustic or otherwise harsh. Systems and methods addressing the shortcomings of current technology are needed.